Computer systems generally have one or more mass memories for storing data. When replacing such a mass memory, for example, the problem arises of the memory generally containing private or confidential data. These data are intended to be erased before the memory is replaced to prevent misuse of the data. In this case, simple erasure using the operating system generally does not suffice to irrevocably erase the data since the assignment of the file names to physical memory addresses of the mass memory is erased only at the file system level. At the physical level, the data remain substantially in the mass memory. Simple software programs usually suffice to restore these allegedly erased data.
A promising method of erasing these data involves physically destroying the mass memory, the mass memory being demagnetized or mechanically destroyed in another manner, for example. Such methods lend themselves to governments or intelligence services, for example.
However, the mass memories which have been replaced are generally used further, for example, sold in which case it is necessary to securely and irrevocably erase the mass memory by the computer system. In magnetic hard disk drives, there are erasure algorithms for this purpose which generally repeatedly overwrite the memory areas with predetermined bit patterns, with the result that it is virtually impossible to restore the original data.
However, such methods cannot be used in non-volatile semiconductor mass memories since these mass memories fundamentally behave differently from magnetic hard disk memories in terms of organization of data and free storage space owing to the technology. In contrast to a magnetic hard disk memory, it is generally impossible to directly access a particular memory address in the physical memory area in a semiconductor mass memory.
“Reliably Erasing Data From Flash-Based Solid State Drives” by Michael Wei et al. (2011) discloses, for example, that existing erasure methods for magnetic hard disk drives cannot be effectively used in semiconductor mass memories such as solid state drives. Only specific algorithms for controllers of the semiconductor mass memories guarantee the secure erasure of the semiconductor mass memory when implemented correctly. However, this presupposes intervention in the firmware of the respective controller. In addition, firmware is different depending on the manufacturer of the semiconductor mass memory.
It could therefore be helpful to provide a simple method of securely erasing a semiconductor mass memory. It could further be helpful to provide a computer system suitable for carrying out the method and a computer program product.